A characteristic feature of medieval castles in Spain are the detached towers placed along curtain walls and connected by a bridge. They are found throughout Spain (and Portugal) and are called torre albarrana in Spanish; a word believed to be derived from the Arabic barranu = exterior. We shall refer to them as Albarrana towers.
Albarrana towers are a Muslim innovation that first ￼appeared as a defensive feature of Islamic castles in Spain in the 12th century during the Almohad dynasty. The towers have a fairly standard appearance being most commonly square in section and placed several metres in front of the curtain wall. The towers are the same height as the curtain and are accessible by a bridge walkway from the curtain wall. They are perhaps more common in the southern part of Spain where the Islamic influence of the country was longest.
They continued to be built in Spanish castles right up until the 16th century and were popular amongst Christian castle builders in the country long after Muslim ownership of the site had ended, perhaps a reflection of the multicultural masons and craftsmen working in the country. The Military Orders were especially keen on using Albarrana towers and many Templar fortresses in Spain as well as of those of the later Spanish Orders (e.g. Knights of Calatrava) contain them.
In many cases the access bridge between wallwalk and Albarrana tower had a removable wooden section allowing the tower to be isolated from the curtain in the event of it becoming taken by attacking forces. From the top of one of these towers a defender has a commanding view of large sections of curtain wall and is able to see and attack any enemy forces attempting to gain entry along it.
The more usual flanking towers, projecting outward from the curtain wall but remaining a part of it, commonly seen in castles throughout Europe, were also widely employed in Spain and date from the earliest Muslim occupation (e.g. Almeria, Andalusia)..￼ However, as developments in design and effectiveness of mural towers in other parts of Europe progressed through the 13th century, (e.g. Chepstow, Gwent), the more sophisticated castles in Spain employed Albarrana towers.
So although integrated flanking towers, both round and square section, were built into the very earliest Spanish medieval fortifications (e.g. the 9th century Banos de la Encina) the divergent evolution from those of northern Europe matured to produce the very local Albarrana style. This should not surprise us too much as the history and cultural mix that was present in Spain during the middle ages produced many unique and distinctive styles of architecture and art
The very first use of the Albarrana tower has not been conclusively established but many scholars in Spain believe that Torre de Despantaperros in Badajoz (Extremadura) is the earliest. This tower was built by the Almohad dynasty of Muslims in the late 12th century. This tower was constructed during the refurbishment of the original Islamic alcazaba or fortified city, by King Abu-Yakub-Yusuf in 1170 and is still a major landmark in the city today. Octagonal in plan, this tower is positioned in front of the main walls of the city and has a solid base rising to the second floor level, which has chambers, and small arrow loops within..
Variations in style
Although having said a standard approach was used in the design of Albarrana towers there was a wide variation within the theme. Most examples are solid in construction from the base to the platform on top (e.g. Trujillo, Extremadura; Jaen, Andalucia), but some examples have galleries or chambers in the upper stories (e.g. Escalona, Castilla la Mancha).
Parallels in other countries
Albarrana towers are almost exclusively confined to the Iberian Peninsula. Even in other parts of the medieval Muslim world this defensive feature was not adopted. There are a few examples of detached towers in other parts of the world but the small number that do exist are all single towers and nowhere do we find rows of detached towers as we do in Spain and Portugal. Nor are they positioned to provide defensive cover to parts of the curtain wall as the Spanish ones do but rather to protect vulnerable approaches etc.
Rare examples are at castle Trifels, Germany, where a solid detached tower is joined to the main wall by a narrow bridge and at Aleppo in Syria where a large square detached tower on both sides of the citadel guards the ditch and entrance to the medieval city. Neither example follows the exact principal of the Iberian towers and are clearly not influenced by them.
A more interesting example can be found at Pontefract castle in Yorkshire and is the only Albarrana tower known to the author in the UK. Now reduced to a few courses of ruinous basement masonry this tower, known as Swillington Tower, was a square tower rising to three stories and attached to the main curtain wall by a bridge at wall walk level. Built as an addition to the defences of Pontefract castle in the late 14th century, (1399 – 1405) commenced at the time of the death of John of Gaunt (d. 1399) who inherited Pontefract castle on becoming Duke of Lancaster in 1362. Swillington Tower was constructed to defend an exposed section of curtain not adequately protected by the flanking towers of the wall. It might be speculated that the planning and design of this tower was established during Gaunt’s lifetime and thus would provide, through his many years campaigning in Spain, a link and influence to this unusual English castle feature.